MDN上的示例代码

Posted 2020-10-04

1.bind方法时，提到了偏函数的用法，给函数提供一个默认的参数。


var list = function(){
    return Array.prototype.slice.call(arguments);
}

var list1 = list(1,2,3);
console.log(list1);
//创建一个函数，有一个默认的起始参数
var plist = list.bind(undefined,5);
console.log(plist());
console.log(plist(1,2,3));

2. setTimeOut()时，用bind绑定this的值。

function flower(){
    this.petalCount = Math.ceil(Math.random()*12)+1;
}
flower.prototype.declare = function(){
    console.log("I am an beautiful flower with "+this.petalCount+" petals.");
}
flower.prototype.bloom = function(){
    global.setTimeout(this.declare.bind(this),1000);
}

var aFlower = new flower();
aFlower.bloom();

3.setTimeOut 的使用
var array = [‘one‘,‘two‘,‘three‘];
Array.prototype.myMethod = function(passed){
    return arguments.length>0?this[passed]:this;
}

console.log(array.myMethod()); // one two three
console.log(array.myMethod(1)) //two

// setTimeout(function() {
//     console.log(array.myMethod())
// }, 1000);